With the development of technologies for digital signal processing, storage media, and transmission methods, traditional voice services have developed into multimedia services. As a result, various compression technologies for storing and transmitting a large amount of data have been under study. In particular, standard specifications for technologies for encoding and storing digital moving picture information have been established. For example, The International Telecommunication Union (ITU) established H.261 and H.263 that are standard specifications for moving image services in wired and wireless communication network environments, and the International Organization for Standardization (ISO) prepared MPEG-1, MPEG-2, and MPEG-4 that are moving picture standard specifications. With the rapid spread of wireless communications, specifications on moving picture compression technologies capable of providing improved compression under various communication environments have become desirable.
Recently, the H.264 moving picture compression standard has been established by ITU and ISO, which can provide more flexibility in coping with various network environments and greater efficiency of encoding moving pictures. However, according to the H.264, an encoder and a decoder may be more complicated than those of a conventional compression method. In particular, the encoder may determine more parameters and encoding modes than in a conventional standard and the decoder may perform more calculations than in the conventional standard due to a de-blocking filter or motion compensation in units of quarter pel.
In general, according to the H.264, in order to perform motion compensation, quarter pel interpolation is performed to enlarge an image four times. Then, motion estimation is performed. In order to perform the above-described operations, quarter precision may be used, which may increase the processing complexity. Also, according to the H.264, a fixed macro block generally is not processed, but various kinds of sub-macro blocks are processed. Such a variable block size characteristic may need to be considered during the quarter pel interpolation.